20626 (JE215) Adjustable Dual
Power Supply Kit
General Description:
The 20626 is a dual power supply with
independent adjustable positive and
negative output voltages. A separate
adjustment for each of the supplies
provides the user unlimited applications
for IC circuit voltage requirements. The
supply can also be used as a general all
purpose variable power supply.
- Adjustable regulated power supplies
positive and negative 1.2VDC to 15VDC
- Power output (each supply): 5VDC @
500mA, 10VDC @ 750mA, 12VDC @
500mA, and 15VDC @ 750mA
- Two 3-terminal adjustable regulators
with thermal overload protection
- Heat sink regulator cooling
ITEM
IC1
IC2
C1, C2
C3, C4
CR1, CR4
LED1
R1
R2, R5
R3, R4
P1
T1
QTY. PART NO.
1
23579
1
23819
2
609705
2
33662
4
35975
1
94511
1
690865
2
690689
2
35503
1
42042
1
29226
2
42622
1
20642
2
40970
6
42446
2
42463
2
40943
10
42420
4
32011
20634
DESCRIPTION
Regulator, Adj. Pos., LM317T
Regulator, Adj. Neg., LM337T
Capacitor, Electrolytic, 2200uF 35V
Capacitor, Tantalum, 1uF 35V
Diode, 1N4001
Red T1 ¾ LED, Diffused Lens
¼ Watt, 1k ohm (brown-black-red)
¼ Watt, 180 ohms (brown-gray-brown)
¼ Watt Potentiometer, 2.5k ohms
6 foot power cord, AWG 18/2
Power Transformer, 12.6VCT @ 2A
Heatsink, THM6030 or Equivalent
Printed Circuit Board, JE215-1
Screw, PH 4-40 x 3/8"
Screw, PH 6-32 x 3/8"
Washer, split lock, #6
Hex Nut, 4-40
Hex Nut, 6-32
Rubber bumper feet SJ5012 or equivalent
Kit instructions for JE215
Assembly Preparation and Procedures
1. Important: Identify all parts on parts list before
proceeding.
2. Suggestions: simulate board assembly by placing
the components in their actual place on the picture
assembly (see figure 1 or figure 3), then transfer
components to the actual board during assembly.
3. Tools required: small soldering iron (27 watt to 35
watt), resin core solder (0.3" diameter, SN60 or SN63.
Do not use acid core type or 50/50 solder), small
sponge (water dampened) for cleaning solder tip,
small wire cutter and stripper, small long nose pliers,
screw driver, plastic electrical tape, multimeter that
can read resistance, capacitance, and voltage
(preferably digital)
Component wire stripping, bending, and lead spreading
T1 (Power Transformer)
OUTPUT SIDE (12.6VCT @ 2A) with RED wire as center tap.
Opposite side of transformer are two yellow wires (input side)
for 115VAC input.
IC1 and IC2 Adjustable
Voltage Regulator
Blue wire
default length
8" with 0.4"
stripped and
tinned end
Black wire
default length
8" with 0.4"
stripped and
tinned end
0.400"
Red wire
(center tap)
default length
8" with 0.4"
stripped and
tinned end
Recommend to cut wires on power
transformer to 3.5" in length, strip ¼” twist
bare wires and tin (note: do not cut the
wires while stripping)
Recommended lead spread for
voltage regulator. For
datasheets of part number
23579 (LM317T) and 23819
(LM337T) please proceed to our
website at www.jameco.com
C1 and C2 Electrolytic Capacitor
Overlap and
solder the cut
lead if lead length
not long enough
to solder on
board.
Component lead bending and
clippling
+
PCB BOARD
-
Note: extension lead not required if lead of
one end of capacitor is long enough to
solder on the board.
Bend leads slightly to keep
components on the board before
soldering. Solder leads and clip
excess material.
Soldering Tips:
1. Feed the solder to the crack between the iron tip and the solder pad next to the component lead.
2. Leaving the iron tip too long on a pad will cause the pad to lift, as well as damage the component. Allow
approximately 2 seconds per solder joint.
3. Using too much solder can cause the solder to bridge across traces and pads.
4. Keep iron tip clean by wiping the tip across a water dampened sponge – frequently.
Assembly Instructions:
READ ALL THE INSTRUCTIONS BEFORE STARTING
1. Printed wiring board assembly. See assembly figure 1, figure 2, and figure 3.
1.1 Start the board assembly by placing the printed circuit board to the position shown on the assembly
picture (see figure 1 (component side), figure 2 (solder side).
1.2 Insert diodes CR1 thru CR4 as shown. The polarity band on each of the diodes must be placed as
shown on the assembly (see figure 1 (component side) and figure 2 (solder side). Mount all diodes 1/8" above
the board. Solder and clip leads.
1.3 Insert resistors R1, R2, and R5 (see figure 1). Be sure that the color coded values are properly
placed. Solder and clip leads.
1.4 Insert capacitors C3 and C4. Be sure that the positive (+) polarity lead on each of the capacitors is
placed correctly on the printed circuit board. Solder and clip leads.
1.5 Install transformer T1 by first inserting the leads into the board before securing it down with the
hardware. The CT (center tap) lead is different in color in this group of 3 wires and must go into the hole
marked “CT” (see figure 1).
1.6 Insert regulators IC1 and IC2 (see figure 1). Push leads about 1/8" into the board. Do not solder
yet. Be sure the correct regulator (IC) is places into the correct position.
1.7 Install the heat sinks behind the IC’s as shown. Push the heat sink into the holes. Allow 1/8" of air
space between the bottom of the heat sink and top of the board. Secure IC’s to heatsink using #4 screws
(hardware). Solder IC leads and clip excess leads as required.
1.8 Insert capacitors C1 and C2. Be sure that the polarity leads are properly placed in the correct
nodes. Push the capacitors against the board and bend each leads 90 degrees into the solder trace. Solder about
1/8" to ¼” of the leads to the solder pad (solder side of the board) and clip excess leads.
1.9 Insert light emitting diode (LED1). Note the (-) polarity lead which is is the flat side of the LED
placement. Adjust the LED by leaving approximately ¾” of leads above the board. Solder and clip excess
leads.
1.10 Insert adjustable resistors R3 and R4. All leads must be straightened before installing. Mount
resistor body flush to the board (component side). Solder and clip excess leads.
Assembly Instructions (continued):
1.11 Install jumper wire as show on figure 1 and figure 2 (option for a switch). Use clipped component
lead wire. Solder and clip excess leads.
1.12 Strip power cord P1 insulation back about ¼”. Twist wire leads and insert into location as shown
(see figure 1 and figure 2). Bend twisted wire leads of power cord flush against the solder pads and solder. As
a safety precaution against electrical shocks, place two layers of ¾” wide plastic electrical tape over the
120VAC input traces. A cable clamp may be used, secured by the transformer to relieve the strain on the
power cord leads.
1.13 Insert 4 no. 6 screws from the bottom of the board for the output terminals as shown (see figure
x). Tighten the first nut (4) on top of the board. Hand tighten the second nut (4) over the first.
1.14 Place bumper feet (4) approximately as shown (see figure x) to the bottom of the board.
1.15 Cut power supply indent. Labels from instruction sheet, glue, or tape the board as shown (see
figure x).
2. Final Assembly
Do not attempt to plug in the power cord until a final check has been made to verify the correctness of
all assembled components. Components IC1 and IC2 will be permanently damaged if their placement is
accidentally swapped and diodes CR1 and CR2 will blow if their polarity placement is reversed. Place a check
(4) in each of the circles on the assembly picture as you go over each component.
Power Supply Voltage Adjustment:
1. The Kit 20636 (JE215) power supply voltage can be varied by turning adjustable resistors R3 for positive
power supply and R4 for negative supply (see figure 1 for location of R3 and R4). Use DC voltage meter for
correct voltage setting.
2. For dual adjustable positive (or dual negative outputs, reverse the leads on one of the supplies. However,
when used in this manner, each of the load must be in separate use, i.e. not electrically connected together.
Safety Notes:
1. Never use the power supply on metal surfaces.
2. Allow adequate air ventilation to cool.
3. Unplug power cord when not in use.
Trouble Shooting Tips:
1. No voltage outputs across terminals –
1.1 A) check power cord for correct wiring and 115VAC on printed board pads. B) check for
12.6VCT on secondary leads of transformer T1. C) check for improper placement of C1 and C2
(polarity) – should have approximately 18.5VDC when measure across each capacitors. D)
check for polarity on diodes CR1 to CR4, diodes will blow if polarity bands are placed
backwards.
2. Everything functions except for LED1 which does not light up –
2.1 reverse lead mounting – led anode and cathode side could be backwards.
3. Output voltage problems –
3.1 regulators IC1 and IC2 are reversed. Possible permanent damage. If unsure of pin configuration
please proceed to our website for datasheet on IC1 and IC2 regulator (refer to figure 1 for
proper placement on IC1 and IC2 on PCB board).
3.2 A) output voltage stays high – open connections in R3 and R4 terminals, check for soldering joints.
B) output voltage stays low and does not change – shorted R3 and R4 terminals, check for solder
bridging.
3.3 Output varies and is difficult to adjust – check for placement reversal of C3 and C4, and R3 CR3
and CR4.
4. Output voltage drops under load –
4.1 check capacitors C1 and C2 for proper value and correct polarity.
20626 (JE215) Adjustable Power Supply Kit
Important disclaimer: to the fullest extent permitted by applicable law, Jameco expressly disclaims the
implied warranty to fitness for a particular purpose. Customer should understand that Jameco does not may
any representation that products purchase will suit customer’s particular purpose. Customer must rely on own
customer’s skill or judgement in selecting sutable products for customer. To the extent any implied warranty
is applicable, such warranty shall be limited to 90 days from date of purchase.
Limitation of liability: Jameco’s liability shall be limited to the repair or replacement of defective products in
accordance with the Jameco limited warranty. Jameco shall not be liable for any incidental, special or
consequential damages for breach of any warranty, expressed or implied, directly or indirectly arising our ot
Jameco’s sale of merchandise, including any failure to deliver any merchandise, or arising out of customer’s
installation or use, whether proper or improper, of the product, separately or in combination with other
equipment, or from any other cause.
Warranty: Jameco warrants the equipment to be free from defects for a period of 90 days from date of
purchase. If found to be defective, these products will be replaced with a new unit, not repaired. No units will
be accepted past the 90 day warranty for repair or replacement. There is no charge for any replacement.
Equipment or parts which have been subject to misuse, accident, alteration, neglect and/or unauthorized repair
are not covered by the warranty. Seller shall have the right to final determination as to existence and cause of
defect.
JE215 POWER SUPPLY
SCHEMATIC DIAGRAM
IN
IC1
ADJ
OUT
R2
NC
12.6VAC
+
+
+
C3
C1
CR3
R3
GND
POS SUPPLY
CR1
R4
-CR2
LED1
R1
+
GND
+
C2
CR4
C4
ADJ
IN
IC2
R5
OUT
--
NEG SUPPLY
JW1
PRINTED CIRCUIT BOARD COMPONENT SIDE
FIGURE 1
Center Tap Lead of
Transformer
Heatsink Mounting
Holes
1N4001
IC2 (LM337T)
C1
AC INPUT
R5 (180 ohms)
R3
+
-V
GND
Transformer
Input
Output of
Transformer
1N4001
--
+
C4
R1 (1k
ohm)
+
Transformer
Input
C3
1N4001
Output of
Transformer
GND
R4
+V
+
AC INPUT
1N4001
R2 (180 ohms)
C2
Heatsink
Mounting Holes
IC1 (LM317T)
Center Tap Lead of
Transformer
Mounting Holes of
Heatsink
AC Input
Input Leads of
Transformer
Input Leads of
Transformer
AC Input
Mounting Holes of
Heatsink
PRINTED CIRCUIT BOARD SOLDER SIDE
FIGURE 2
Note: C1 and C2 are
2200uF @ 35V
COMPONENT LAYOUT (COMPONENT SIDE OF PRINTED CIRCUIT BOARD)
FIGURE 3